The use of masks and social distancing have become mandatory measures in certain settings to prevent the spread of the coronavirus. Now, through computer simulations, an international team of researchers has revealed how effective face masks are in preventing spreading contaminated particles, even when we just breathe.
The new study, published in the journal Physics of Fluids, was based on a model that differs from previous work focused on the spread of droplets in the air when coughing or sneezing. Specialists from Stony Brook University, Harvard, ETH Zurich and Hanyang University simulated normal breaths, which produce periodic jets of droplets, at speeds less than one-tenth that when driven by coughing or sneezing.
The results showed that without a mask the drops can travel up to 2.2 meters through the air in 90 seconds. While, using a mask, that distance was only 0.72 meters, well below the suggested social distancing space to avoid contagion.
The team concluded that even normal respiration produces a complex field of action that can spread the particles over long distances, so a mask dissipates the kinetic energy of the jet produced by an exhalation, limiting the movement of the virus-laden droplets.
“Our results show that normal respiration without a face mask generates periodic entrainment jets and main circular vortex rings that propagate forward and interact with the vortex flow structures produced in previous respiration cycles.” precise the author Ali Khosronejad.
Because wearing a mask partially redirects exhaled breath downward, the risk of suspended droplets remaining in the air is substantially reducedthe experts explained.
The authors hope that their work will encourage people to maintain social distancing and the use of face masks, and say that in future models they plan to add more variables to obtain more precise conclusions.